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. ENGINE. 7

No. 531,286. I Patented Dec. 18, 1894.

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'E. J. WOOLF. ENGINE.

No. 531,286. Patented Dec. 18, 1894.

' Inventor ZVZ iw/esses l B 4 l'lfoi y UNITED STATES PATENT- OFFICE.

ELLIS J. WOOLF, vOF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO THE WOOLF VALVEGEAR COMPANY, OF SAME PLACE.

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SPECIFICATION forming part of Letters Patent, No. 531,286, datedDecember 18, 1 894. Application filed June 2, 1894. Serial No. 513,240.(No model.)

To all whom it may concern:

Be it known that I, ELLIS J. WOOLF, a citizen of the United States,residing at Minne apolis, in the county of Hennepin andState ofMinnesota, have invented certain new and useful Improvements in Engines;and I do hereby declare the following to be a full,clear,

I and exact description of the invention, such 1894, entitled engines.

My present invention has for its object to provide certain furtherimprovements in the classes of engines above referred to, with a view ofsimplicity and economy of construction and. efficiency of action. v v Tothese ends, my invention consists of the novel features hereinafterfully described and defined in the claims.

The accompanying drawings illustrate my invention, in which like lettersrefer to'like parts. Figure 1 is a central vertical longitudinalsection,through my preferred form of engine. Fig. 2 is a similar view,showing a modified form of the dividing partition between the two tandemcylinders. 7 I

The high and low pressure cylinder castings 1 and 3 are settandemand'fitted with pistons 3 and 4 connected by a common rod 5, extendingthrough a dividing partition 6, constituting the inner end of eachcylinder. The two cylinders have a common valve-seat 7, which is locatedon the low pressure cylinder." On th'esaid seat 7, is located a twopartor double acting valve 8 within the valvechest 9, and provided withthevalve-rod 10. In respect to the distribution, the valve-seat 7 andthe doubleacting-valve 8 are substantially like the preferred form ofvalve and valve-seat, shown in my above noted pending application,Serial No. 503,047, filed March 9; 1894. The distribution is independentfor each (so-operating pair of cylinder ends; and

"the valve travels with the piston, when out 5 5 ting ofi admission tothe high pressure ports both as in the said application, Serial No.

503,047. In respect to the valve itself, it is not deemed necessary, forthe purposes of this case, to give any further details; but in re-.spect to the seat, it is desirable to distinguish the outer end highpressure port a, the inner end high pressure port a, the low pressureports I), and the final exhaust port 0. The

said final exhaust port 0 is located centrally of the seat; the lowpressure ports b are located on opposite sides of the final exhaust port0 and are of substantially equal size and length; and the high pressureports a and a. are located one external of each of the respective lowpressure ports b b.

In virtue of the fact, that the two pistons 3 and 4 are connected to thecommon rod 5, and, of course, move in a common direction, it isnecessarythat the outer end of the high and the'outer end of the lowshould co-operate with each other; and that the inner end of the highand the inner end of the low should co operate with each other. Hence,it is neces-. 'sary that the outer end high pressure port a 'of thevalve-seat 7 should connect with the outer end of the high pressurecylinder; and this is accomplished, in my improved construction hereinshown, by sectional passages or ports 0!. and a respectively, formed inthe cylinder castings, and uniting into a continu ous passage, inthecommon flange joint,which connects the inner ends of the saidcylinder castings. The port section a which is formed in the lowpressure cylinder casting 2, is formed continuous with the valve-seatport a and clears all the other ports in the valveseat.

The dividing partition 6, which separates the two cylinders is locatedin the low press- 5 ure cylinder casting 2, coincident with and forminga part of the bridge will dividing Hence, the inner end high pressureport a too of the valve-seat is located entirely within the low pressurecylinder casting 2; and the said port a has continuous therewith a clearance chamber a, formed byan enlargement of the low pressure cylindercasting, which clearance chamber opens directly into the inner end ofthe high pressure cylinder. In virtue of the facts above noted, as tothe location of the dividing partition, the inner end high pressure porta and the clearance chamber a, it follows that the low pressure cylindercasting 2 is extended beyond the said port a, and clearance chamber a,to form the joint flange uniting the two cylinders and the two sectionsof the high pressure port passages a a formed in the said castings. Theclearance chamber a continuous with the inner end high pressure port 0.,serves to compensate for the large clearance in the valve seat highpressure port a, and the passages a. a therefrom, to the outer end ofthe high pressure cylinder. Otherwise stated, this clearance chamber ais required, in order to compensate for the large clearance at the outerend of the high pressure cylinder incidental to the necessary length ofthe outer end high pressure port thereto; and with this arrangement,equal volumes may be afiorded on the opposite sides of the high pressurepiston 3. As shown, however, the said clearance chamber a is slightlysmaller than would be necessary, to afiord the complete compensation,for the space in the passages a a a and the remainder of the necessaryclearance, at the inner end, is obtained by recessing the inner face ofthe high pressure piston 3, as shown at a What has so far been said,applies, in all respects, to the constructions shown in both views ofthe drawings; but in the form shown in Fig. 1, the dividing partition 6is made removable, and is held to its seat by set-screws 11, tappedthrough the joint flange of the high pressure cylinder casting andbearing against the said partition. This removable partition might alsobe secured in position and be held to its seat by lugs projecting eitherfrom the plate or from the joint flange of the high pressure cylindercasting.

In the modification shown in Fig. 2, the dividing partition 6,separating the two cylinders, is shown as formed integral with the lowpressure cylinder casting, and as provided with a recess d opening up tothe atmosphere, for access to the piston rod packing. For all purposesof operation, the results are the same, so far as the action of theengine is concerned; but the removable partition 6 is an advantage, foraffording access to the low pressure cylinder from the high pressureend. In virtue of this and the general construction, it is obvious, thatby the removal of the joint flange nuts (not shown), the two cylindercasting may be separated, the partition 6 be removed and access bealforded to all parts of both cylinders; and that, in virtue of thelocation of the inner end high pressure port a. wholly within the lowpressure cylinder cast-j ing, and the relative arrangement of thesectional port passages a a uniting in the joint flange connecting thetwo cylinder castings, no pipe couplings or uncouplings are required inseparating or putting together the two cylinder castings. The set-screws11 having been once properly set, no other adjustment will be requiredto bring the partition 6 into proper position, under the proper tension,when putting together the two cylinders after separation. The tighteningof the joint flange nuts will properly seat the said plate. Moreover, itis obvious that, inasmuch as the removable partition plate 6 is oflarger diameter than the low pressure cylinder,and is seated from thehigh pressure end, the steam in the high pressure cylinder, co-operatesto hold the said plate to its seat. It has already been noted, that,upon the separation of the two cylinder castings and the removal of saidpartition plate 6, access is alforded to both cylinders; and it isequally obvious and should be noted that both pistons may, then, beremoved from their cylinders, without separation of either from theircommon rod.

I have shown a starting valve 12 on a sidewise extended portion of thevalve-seat, cooperating with passages 13, in communication with the highpressure ports a a in the said seat. These valves 12 are on a common rod14, operative by hand, for converting the compounds into simple actingengines, at will. The said valves 12 and the ports 13, for co-operationtherewith, are identical in construction and relation to thedistribution valves and their seats, with the starting valve shown,described and claimed in my above noted pending and allowed application,Serial No. 481,297. The valves 12 normally close the ports 13.

What I claim,and desire to secure byLetters Patent of the United States,is as follows:

1. In a tandem compound engine, wherein the distribution is eifectedfrom a common seat on the low pressure cylinder and the pistons move inthe same direction, thecombination with the outer end high pressureport, of the inner end high pressure port, having continuous therewith aclearance chamber formed in the low pressure cylinder casting an openinginto the inner end of the high pressure cylinder, whereby the excessiveclearance caused by the necessary length of said outer end port may becompensated for by said inner end clearance chamber, substantially asdescribed.

2. In a tandem compound engine, wherein the distribution is eifectedfrom a common seat on the low pressure cylinder and the pistons move inthe same direction, the combination with the outer end high pressureport, of the high pressure piston recessed on its inner face to affordinner end clearance, and the inner end high pressure port havingcontinuous therewith a clearance chamber formed in the low pressurecylinder casting and opening into the inner end of the high pressurecylinder, whereby the inner end cident with the bridge wall dividing thein ner high and low pressure ports, and forming the inner end of bothcylinders, substantially as described.

4. In a tandemcompound engine havinga common valve-seat located onthelow pressure cylinder, the combination with the low pressure cylindercasting having an enlarged recess at its inner end, for forming an innerend high pressure clearance chamber, of the removable partition, seatedin said recess coincident with the bridge wall dividing theinner highand low pressure ports and for-m ing the inner end of both cylinders,and setscrews tapped through the high pressure cylinder flange andbearing against said partition for holding the same in position,substantially as described.

In testimony whereof I aflix my signature in presence of two witnessesELLIS, J. WOOLF.

Witnesses:

E. F. ELMORE, J As'F. WILLIAMsoN.

